The Reds had been above criticism since preseason, a side so unbelievably good it locked up the Supporters’ Shield two months early.

It’s a team that, with five regular-season games remaining, already owned the eighth-best record in MLS history — six points off the Galaxy’s record 68-point season.

Until Wednesday night, Toronto FC hadn’t lost at home this year. The Reds have been nothing short of sensational, setting record after record amid being referred to as the best team in MLS history — a label backed by both the eye test and numbers.

Until now, they’d avoided returning to the bad place.

Toronto FC has had challenges — in Dallas, in New England, in Columbus — but not many. At times, Toronto FC’s success this season hasn't seemed real. That’s how good the Reds have been.

LARSON ON WHAT WENT WRONG AGAINST MONTREAL

But in a 5-3 loss to visiting Montreal, Toronto FC returned to its bad place — a place Reds fans haven’t seen since the middle of last season, when TFC still was finding its identity under a semi-new coach with new, winning ideas.

It’s a loss that shouldn’t cause pause or concern or any of the other overreactions you might read or hear in the coming days. This was a loss that showed how the margin for error in this sport, this league, are paper thin.

“You can lose, and you can give up a lot of goals,” coach Greg Vanney said. “If you make errors, Montreal will punish you.”

It also was a result that showed how defensive errors compounded by goalkeeping errors can turn a game on its head in the regular season. Or, a month from now in the post-season, where the Reds remain poised to be the top seed.

Amid career seasons, centreback Eriq Zavaleta and goalkeeper Alex Bono both had career stinkers. Zavaleta’s miss-clearance metres from goal was followed by another clearance from Bono that deflected off Ignacio Piatti and into TFC’s goal before the game was 10 minutes old.

Two minutes later, Zavaleta’s turnover ended with Marco Donadel striking a knuckling effort from distance that somehow beat Bono, bringing back visions of the howler TFC’s ’keeper conceded last season against nine-man San Jose.

Piatti put the game out of reach less than a half-hour in after undressing TFC along the left edge of the area, cutting inside and unleashing a blast that bulged the netting near the back post.

Just like that, TFC’s unblemished season was besmirched by a rival that was essentially handed five goals by a team that had conceded just 26 times all season, leading to a sizable portion of the 28,898 in attendance heading for the exits early.

When cameras panned to Vanney and assistant Robin Fraser early in the second half, both looked dumbfounded after an egregious turnover from Steven Beitashour put Anthony Jackson-Hamel in alone to score on a breakaway.

Jackson-Hamel tacked on Montreal’s fifth minutes later when the Impact exploited another turnover that, again, lead to a 2-on-1 against Bono.

A pair of late header goals from Tosaint Ricketts only served to make the scoreline slightly less embarrassing.

“There were a lot of guys off tonight,” Vanney added. “Just as a group, we weren’t clicking.”

But in match most TFC fans will want to forget, Vanney likely learned a number of things entering the final month of the regular season — both good and bad for certain players playing in place of the club's big guns.

Armando Cooper is likely to be locked away for the rest of the year given the number of poor decisions he made in possession throughout Wednesday night’s game. Further back, Vanney could have a decision to make when Nick Hagglund returns from injury.

Nico Hasler also looks like he should be TFC’s starting right fullback moving forward — and not just because of Beitashour’s up-and-down night. Hasler has been good since his arrival.

Then there’s Ricketts, who reminded TFC fans this week his athleticism and pace could be the difference in a tight playoff series.

Still, this was a night where individual storylines were swallowed up by a sobering defeat that ended an 11-game unbeaten streak.

Perhaps the Reds simply ran out of gas without Sebastian Giovinco, Jozy Altidore and Victor Vazquez. These things happen over the course of a 34-game season — especially in MLS. Many of us were waiting for it.

That said, losing in this manner, in a derby, is something that can alter the course of a season if things aren’t turned around quickly.